ServiceWorkerProviderHost: Update comment about running_hosted_version()

One comment was:
~~~
  // This is nullptr when the worker is still starting up (until
  // CompleteStartWorkerPreparation() is called).
  ServiceWorkerVersion* running_hosted_version() const;
~~~
This is not true (anymore?). The pointer is constant and never null.

Bug: 1031542
Change-Id: I44907a27c65a6ad228014f0ad4fbeded8bbab807
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2083456Reviewed-by: Makoto Shimazu <shimazu@chromium.org>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#746717}

content/browser/service_worker/service_worker_provider_host.cc

@@ -89,12 +89,6 @@ ServiceWorkerProviderHost::~ServiceWorkerProviderHost() {
   container_host_.reset();
 }
 
-ServiceWorkerVersion* ServiceWorkerProviderHost::running_hosted_version()
-    const {
-  DCHECK_CURRENTLY_ON(ServiceWorkerContext::GetCoreThreadId());
-  return running_hosted_version_;
-}
-
 void ServiceWorkerProviderHost::CompleteStartWorkerPreparation(
     int process_id,
     mojo::PendingReceiver<blink::mojom::BrowserInterfaceBroker>

content/browser/service_worker/service_worker_provider_host.h

@@ -57,10 +57,9 @@ class CONTENT_EXPORT ServiceWorkerProviderHost {
 
   int provider_id() const { return provider_id_; }
   int worker_process_id() const { return worker_process_id_; }
-
-  // This is nullptr when the worker is still starting up (until
-  // CompleteStartWorkerPreparation() is called).
-  ServiceWorkerVersion* running_hosted_version() const;
+  ServiceWorkerVersion* running_hosted_version() const {
+    return running_hosted_version_;
+  }
 
   // Completes initialization of this provider host. It is called once a
   // renderer process has been found to host the worker.